1. Field of the Invention
The present invention relates to pipe clamps and, more particularly, to clamps for attaching overhead sprinkler head supporting pipes.
2. Description of the Prior Art
Overhead sprinkler heads are in fluid communication with and supported by pipes forming a part of a fire dousing watering system. Building codes require that the pipe ends in proximity to the supported sprinkler heads be capable of supporting an axially imposed force of 700 lbs. In addition, the clamps must be able to withstand substantial vibration for a period of time. As a practical matter, such clamps must permit relatively facile axial repositioning of the pipe to correctly locate the sprinkler head with respect to the ceiling. Moreover, any ceiling replacement with an accompanying change in ceiling height should be accommodatable.
A number of clamps have been developed which provide adequate retentive force, readjustment of pipe position or sufficiently firm anchoring of the clamp to an anchor point. However, few of the prior art clamps permit adjustment from below with a simple tool, such as a screwdriver. In the event adjustment is only possible from above, removal of the finished ceiling to provide access for a workman may be necessary. Such requirement complicates the procedure and renders it more difficult to quickly set an attached sprinkler head at the correct height. A requirement for using two tools simultaneously prevents a workman from using one hand to relocate the sprinkler head during loosening and retightening of a clamping device. Because cost is always a factor and as a large number of clamps may be necessary for installation of sprinkler heads in any particular building, clamps for this purpose must be relatively inexpensive without jeopardizing structural strength or ease of use. This combination of benefits is not available from the known prior art sprinkler head pipe clamps.